Safety joint



W. L. CHURCH June 17, 1947.

SAFETY JOINT Filed March 9, 1944 2 Sheets-Sheet, 1

1mm LL01 W. L. CH URCH June 17 1947.

SAFETY JOINT Filed Max-ch 9, 1944 2 Sheets-Sheet 2 3 m 2mm JLLML Patented June'17, 1947 2,422,223 SAFETY JOINT H Walter L. Church, Houston, Tex. ApplicationMarch 9, l94 4 serial No. 525,731

1 Claim. (c1. 285-146) This invention relates to a safety joint.

An object of the invention is to provide a joint designed to be connected into an operating string, such as a string of rods or a tubular string of pipe and which may be readily disconnected.

The safety joint has been specially designed for use in a tubular operating string which may be used in well drilling or other operations carried on in a well bore.

It often becomes necessary to separate a drill stem or other operating string in order to remove it from the well as for example when a drill or,

packer or other similar tool or appliance becomes stuck in a well bore so that it cannot be with drawn, it then becomes desirable to unscrew the operating string, at the safety joint, be removed and saved. i

The type of joint herein described has been designed for the purpose above indicated.

With the above and other objects in view, ,this invention has particular relation to certain novel features of construction, arrangement of parts and use, an example ,of which is given inthis specification and illustrated in the accompanying drawings, wherein Figure 1 shows a side elevation of the joint partly in section.

Figure 2 shows a cross sectional view taken on the line 2--2 of Figure 1.

Figure 3 shows a cross sectional view taken on the line 3--3 of Figure 1.

Figure 4 shows a fragmentary perspective view of one of the coupling members.

Figure 5 shows aside elevation of another embodiment of the joint partly in section.

Figure 6 showsga cross sectional view taken on the line 6-6 of Figure 5, and 4 Figure 7 shows a transverse sectional vie taken on the line 'l-'| of Figure 5.

Referring now more particularly to the drawings wherein like nume'raLs of reference designate the same parts in each of the figures, the numeral 1 designates a tubular operating string. This string is made up of a number of sections which are connected by couplings, usually hav ing right hand threads and the string is connected to the drill collar or other appliance to ber 4is notexternally threaded but has, countersunk therein, the upper and lower annular packsloth at it can ing rings 1, I which form fluid tight joints with 4 the inner wallof the lower coupling member 3.

Accordingly when the coupling member 4 is turned to the right, it will be unscrewed from'the lower coupling member 3. I

Screwed onto the lower end of the string I there is a collar 8 whose lower endis reduced and externally threaded and screwedonto said reduced lower end there is 'a tubular skirt, or housing, 9.

The abutting ends of the skirt! and the lower f coupling member 3 are'formed with the jaws l0 and H, respectively, which are shaped to interlock, as shown in Figure 1, when the safety joint is assembled. On the opposite side of the safety joint, from that shown in Figure 1, are interengaging jaws similar tothe jaws l0 and II, shown in Figure 1,-as illustrated in Figure 4.

The upper end of the upper tubular member 4 is outwardly thickened thus forming an external and the upper coupling member may then be screwed into the lower coupling member to home position, as shown in Figure 1 and the upper end of the skirt 9 then connected to the collar 8.

In this position the clutch jaws l0 and II will be interengaged and a frangible pin l8 may then be driven through the transverse keyway I9 extending through the skirt 9 .and through one of the keys I1 so as to secure the skirt 9 and the operating string against longitudinal movement relative to the coupling members during rotation.

or other normal operations of the string and tool orappliance connected to it.

Should the drill, or other tool,-or appliance become stuck in the well so that the same cannot be removed, an upward pull may be taken on the string l and the pin [8 sheared and the skirt pulled upwardly, soas to disengage the laws "1 3 and separated.

thereby be unscrewed and the drill stem or other operating string will be detached and may then be withdrawn and thus recovered.

In the embodiment illustrated in Figure 5, the

jacket 9 may be clutched with the coupling member 3 by the clutch jaws Illa and I id as shown.

In this embodiment, the shear pin I8 has been dispensed with and a frangible nipple 2|] is used to accomplish the same purpose.

The upper end of this nipple has an external,

,annular, downwardly facing shoulder M which is engageable with an inside, annular, upwardly facing shoulder 22 in the collar 8a. This nip- This type of safety joint makes it unnecessary to turn the string or stem to the left to disconnect it so that none of the other couplings connecting the sections of the string or stem are liable to be unscrewed.

What I claim is:

A safety joint comprising two coupling members screwed together, a tubular connecting connecting member adapted to be connected to an operating string and having an inside, annular, rib provided .with a vertical keyway, a longitudinal key on one of the coupling members slidable in the keyway, a clutch between the connecting ple is screwed into the upper coupling member 4 and holds the clutch jaws Illa; I la in clutching relation during a, normal operation of the tool.

The nipple 20 has a deep, inside, annular groove 23 which weakens it 'so that should the drill, or other tool an appliance, become stuck in the well upon an upward pull being taken on the operating string, the nipple 20 will separate at said weakened point permitting the clutch jaws to disengage so that the coupling.member 4 may be unscrewed from the coupling member In other respects, the safety joint shown in Fi ure 5 is the same as that shown in Figure 1.

It is desirable that the safety joint be incorporated into the stem or string at the lower end thereof so that all of the stemor string 30 1,365,730 may be detached and removed from the well.

member and the other coupling member arranged to be engaged and disengaged by movements of the connecting member and a frangible pin through said coupling member and key, accessible for installation externally of the safety joint and normally holding said clutch engaged.

WALTER L. CHURCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date' 1,982,915 Jenks Dec. 4, 1934 1,171,311 Blackwood et a1. Feb. 8, 1916 Sager Jan. 18, 1921 Boynton Mar. 30, 1943 

